1. Field of the Invention
The present invention generally relates to connecting structures and methods for using the same, and more particularly, to a connecting structure used for connecting metal elements and a method using the same.
2. Discussion of the Related Art
Rivets are generally used as connecting structures to connect metal elements together. Referring to FIG. 8, a typical rivet 10 is shown. The rivet 10 is used for connecting a first metal element (not shown) and a second metal element (not shown) together. The rivet 10 includes a collar 11 and a cylindrical portion 12 extending from one end of the collar 11. The collar 11 is gear-shaped and includes a plurality of gear teeth 15. The rivet 10 defines a threaded hole 13 through the cylindrical portion 12 and the collar 11. The rivet 10 defines an annular groove 14 at an end of the cylindrical portion 12 adjoining the collar 11.
To use the rivet 10, the collar 11 of the rivet 10 is pressed into a first corresponding through hole of the first metal element, thus the gear teeth 15 of the collar 11 is inserted into the first metal element and part of the materials of the first metal element are displaced into the annular groove 14 of the rivet 10. Therefore, the collar 11 of the rivet 10 can be tightly engaged in the first through hole of the first metal element. The cylindrical portion 12 of the rivet 10 is received in a second corresponding through hole of the second metal element and a screw (not shown) engages in the threaded hole 13 of the rivet 10. Thus the first metal element and the second metal element are joined together.
Referring to FIG. 9, another typical rivet 20 is shown. The rivet 20 includes a collar 21, a shaft portion 22, and a gear-shaped portion 23. The gear-shaped portion 23 is disposed between the collar 21 and the shaft portion 22. The collar 21 is cylindrical. The shaft portion 21 is a frustum of a cone, thus one end of shaft portion 21 is smaller the other end of the shaft portion 21. The smaller end of the shaft portion 21 is connected to one end of the middle portion 23. The rivet 20 defines a threaded hole 24 through the collar 21, the shaft portion 22, and the gear-shaped portion 23.
To use the rivet 20, the first through hole of the fist metal element corresponds to the gear-shaped portion 23 of the rivet 20 and the second through hole of the second metal element corresponds to a larger end of the shaft portion 22. The larger end of the shaft portion 22 of the rivet 20 is pressed into the first through hole of the first metal element, thus the gear-shaped portion 23 of the rivet 20 is inserted into the first metal element and part of the materials of the first metal element are extruded to cover the shaft portion 22. Therefore, the shaft portion 22 of the rivet 20 can be tightly engaged in the first through hole of the first metal element. The collar 21 of the rivet 20 is received in the second through hole of the second metal element and a screw (not shown) engages in the threaded hole 24 of the rivet 20. Thus the first metal element and the second metal element are joined together.
However, if a thickness of the first metal element and the second metal element is less than 0.8 millimeters, the strength produced by the rivets 1020 for bonding the first metal element and the second metal element will be unduly small, thus the above described rivets 10, 20 are not acceptable when joining such metal elements together. In addition, if a hardness of the first metal element and a hardness of the second metal element are both larger than 90 on the Rockwell Hardness B scale (HRB), the threaded holes 13, 24 of the rivets 10, 20 are easily destroyed by the first metal element and the second metal element, thus the rivets 10, 20 are not the preferred means of joining such metal elements together.
Therefore, a new connecting structure is desired in order to overcome the above-described shortcomings. A method for using the connecting structure to connect metal elements is also desired.